Chemistry - A European Journal最新文献

Aromatic compounds in which a primary or secondary amino group is positioned next (in ortho position) to a guanidino group have been reported as intermediates in a variety of reactions, but are generally prone to cyclization to give 2-amino-imidazoles. Here, we present a comprehensive analysis, based on experiments and quantum-chemical calculations, of the stability and reactivity of these compounds. It is shown that cyclization reactions are triggered by Brønsted and Lewis acids. The analysis discloses strategies allowing to prevent cyclization by careful choice of the guanidino group and/or substituent at the amino group. The results of this analysis allowed the synthesis of first unsymmetrical diguanidinobenzene molecules and coordination compounds with o-amino-guanidinobenzene ligands, paving the way for the development of aromatic compounds with adjacent amino and guanidino groups as a versatile class of redox-active organic molecules.

Metal-organic frameworks (MOFs) have garnered significant attention over the past few decades due to their diverse chemical architectures and tunable physicochemical properties, culminating in the award of the Nobel Prize in Chemistry in 2025. By integrating various metal nodes with organic linkers, MOFs offer extensive opportunities for rational design, controlled synthesis, and multifunctional applications. From structural and functional perspectives, MOFs incorporating rare earth (RE) elements (such as scandium, yttrium, and the 15 lanthanides) constitute a distinct subclass of MOFs. The structural diversity of RE metal-organic frameworks (RE-MOFs) is intrinsically correlated with their unique functional characteristics, which primarily stem from the precise selection of metal centers and the deliberate design of organic ligands. This review presents a systematic overview of the synthetic strategies for RE-MOFs, emphasizing the design and roles of metal nodes and ligand structures, and provides a comprehensive summary of their current applications in detecting volatile organic compounds, small molecules, cations, anions, biomarkers, and temperature, as well as in optical encoding and anti-counterfeiting technologies, and rare eart separation.

Cyclometallated Ir(III) complexes are extensively used in luminescent devices such as Light-Emitting Electrochemical Cells (LECs) due to their high stability and also high luminescence quantum yields. To increase the promising complexes for LEC applications, efforts are focused on the design of molecules with specific ligands that can modulate the emission color as well as the nature of the excited state from which radiative decays occur. In this context, this work presents a study of the luminescent properties of two new Ir(III) complexes containing a ligand derived from 1H-imidazo[4, 5-f][1,10]phenanthroline (dmbip). This study, complemented by theoretical DFT calculations and electrochemical characterizations, shows that, in solution, both Ir(III) complexes exhibit the same emission energy as that of the free dmbip ligand. However, in the solid state, the complexes exhibit phosphorescent emission with a marked red shift of nearly 100 nm relative to their performance in solution. This unusual behavior is due to the presence of a luminescent ³ILCT excited state in the solid state, whose population is favored by the heavy metal center. Furthermore, these complexes were characterized in LEC devices and displayed the same emission profile identified in solid-state photoluminescence.

Photochemistry enables transformations inaccessible through ground-state pathways. We report a sustainable and operationally simple Friedel-Crafts arylation using benzophenone oxime tosylate, in low catalyst loading, as the photoacid generator under inert conditions. The method accommodates a broad substrate scope, affording diarylmethane derivatives in good to excellent yields. Mechanistic studies elucidate key intermediates driving the transformation.

Low-valency multivalent iminosugars have recently emerged as promising inhibitors of the therapeutically relevant enzyme β-glucocerebrosidase (GCase). A new synthetic strategy has been developed to simultaneously build more than one trihydroxypiperidine iminosugar unit onto a polyamine scaffold via double reductive amination (DRA) of a d-mannose derived dialdehyde. Five divalent derivatives, using both aliphatic and aromatic diamines and a trivalent compound based on an aromatic scaffold have been synthesized and evaluated as GCase inhibitors. Only oligomers with an aromatic core (26, 31, and 37) strongly inhibit GCase with IC₅₀ values in the low micromolar range and activity enhancements, when compared to the monovalent counterpart, that confirm the occurrence of a positive multivalent effect. Kinetic analysis for divalent 31 and trivalent 37 revealed a mixed-type inhibition. To rationalize the unexpected behavior of 37, an integrated biophysical and computational approach based on STD-NMR, docking, and MD simulations was employed, allowing to clarify the structural basis for its inhibitory profile and paving the way to the rational design of novel inhibitors able to bridge multiple interaction sites of the target enzyme.

The combination of two photochromic molecules into a multimodal photoswitch offers the potential to generate new properties related to molecular solar thermal (MOST) systems. A system can only be considered suitable for MOST applications if it meets key criteria, including a high quantum yield and an extended half-life of the high-energy isomer. Achieving this combination remains a significant challenge. In this study, we present the coupling of an azobenzene unit (AZO) with a norbornadiene system (NBD) via ester functions to develop new bi- and trimodal AZO-NBD photoswitches that exhibit synergistic effects. Photochemical studies reveal that both the NBD and AZO components of the hybrid are switchable. In one case, all isomer types could be selectively produced. Furthermore, each metastable unit can be switched back independently to its corresponding thermodynamically stable form. The quantum yields and half-lives for the NBD and AZO components of the hybrid system could be determined separately. The integration of AZOs has demonstrated the potential to extend the half-lives of NBDs to up to 122 days in certain cases, as confirmed through comparative analysis with reference systems. The enhanced rate of back-conversion was further facilitated by the presence of TFA as a catalyst.

This Perspective describes an apparent transition in the design and function of synthetic receptors for proteins. It is shown that the original receptor design, geared toward protein recognition, lends itself also to receptor self-assembly and concomitant protein assembly. While evidence for this effect has lain somewhat dormant for two decades, numerous recent examples raise interesting possibilities for innovation in protein binding, encapsulation, and crystal engineering. In a bid to inspire future research and collaboration, I speculate on new receptor designs. Considering current developments with nanocarbon hosts, anionic variants might facilitate protein assembly and the bottom-up fabrication of hybrid materials.

DNA ligation is a fundamental reaction used in a variety of applications, typically performed by T4 DNA ligase. For certain applications, such as DNA data storage, DNA-ligating DNAzymes offer a more stable and cost-effective alternative to protein enzymes. The E47 DNAzyme is among the most efficient DNA-ligating DNAzymes reported, but it still lacks sufficient activity for widespread adoption and requires a highly unstable phosphoimidazole-activated DNA substrate to function. In this study, we performed in vitro selection using a pre-structured library based on E47 and identified sequences with more than a twofold increase in ligation activity, representing the fastest DNA-ligating DNAzymes reported to date. We also screened alternative imidazolide compounds for substrate activation and found that phosphobenzimidazole-activated DNA substrates are significantly more stable, remaining intact for at least 24 h at room temperature. These advances improve the practicality of DNAzymes for ligation-based applications and broaden their potential use in DNA data storage.

Clean synthetic strategies that embrace the inherent structural features of renewable building blocks to obtain biologically active compounds hold great potential to improve the economic viability of emerging biorefineries. Importantly, such an approach is highly beneficial for the sustainable manufacturing of pharmaceutically relevant molecules. Here, we demonstrate a one-step protocol toward biologically active isochromans through the Oxa-Pictet cyclization involving both aromatic aldehydes, including vanillin, and aliphatic aldehydes in combination with lignin-derivable homovanillyl alcohol (1), a prominent aromatic platform chemical obtainable via diol-assisted fractionation. Employing tunable deep eutectic solvents as benign reaction media allows for modulating reactivity under mild reaction conditions, and opens access to a library of isochromans in a single step. Several compounds exhibit promising properties, including PPI inhibition, anticancer, and antibacterial activities, highlighting the benefits of this synthetic strategy and its potential for drug discovery.

With the continuous scaling and integration of semiconductor devices, the demand for advanced chemical-mechanical polishing (CMP) has increased significantly. Consequently, the limitations of conventional abrasives have become increasingly evident, prompting a growing need for next-generation slurries with improved material removal rates, surface roughness, defectivity, and selectivity. This review investigates the physicochemical properties of both ceria-based and nonceria-based nanoparticle abrasives and critically examines recent advances in their application to SiO₂ CMP. Emphasis is placed on understanding how these materials contribute to performance enhancement through chemical interactions, mechanical properties, and structural design. Our findings suggest that overcoming the limitations of the existing slurry systems may require a paradigm shift from relying on single-component abrasives to engineering composite systems with complementary functionalities. Such integrated abrasive design strategies present a practical route toward more reliable and effective CMP solutions for future semiconductor fabrication.